The present invention relates to a device for measuring the liquid content of a gas, and in one aspect to a device for measuring the liquid water content (LWC) in the atmosphere around aircraft, such as helicopters.
Helicopters are particularly susceptible to the build up of ice on their rotor blades and engine air intakes when operating under cold, damp conditions both because of the increase in the weight of the aircraft and because of the rapid loss of lifting efficiency due to the ice layers that build up on the aerofoils. There is, therefore, a need for a device to measure the LWC in the atmosphere around an operational helicopter so that the crew can be given warning when they are flying into icing conditions.
Various techniques, including both optical and platinum-wire measurements, are capable of determining the atmospheric LWC but most of these are complex and require a considerable amount of electronics for control.